Generalized Exponential Markov and Model Output Statistics: A Comparative Verification

Abstract

Abstract We performed a comparative verification of Model Output Statistics (MOS) against Generalized Exponential Markov (GEM), a single station forecasting technique which uses only the surface observation and climatology as input. The verification was performed under three conditions: a “scientific” comparison, where both techniques use the same observation as input; an “operational” comparison, where GEM uses a later observation than does MOS, to simulate the situation where a National Weather Service (NWS) forecaster preparing to make an aviation forecast has a later observation; and a “special operational” comparison, pitting GEM against MOS derived from the previous Limited Area Fine Mesh (LFM) cycle, to simulate the “mid-morning update” operational situation in the NWS where the aviation forecast must be made using previous LFM cycle MOS guidance. Verifications for ceiling, visibility, total cloud amount, temperature, dew-point depression, and wind speed/direction were performed on a full yew of da...